#! /bin/bash    
# cache释放：    
# To free pagecache:    
sync  
sync  
echo 1 > /proc/sys/vm/drop_caches    
# To free dentries and inodes:    
echo 2 > /proc/sys/vm/drop_caches    
# To free pagecache, dentries and inodes:    
echo 3 > /proc/sys/vm/drop_caches
